Hypertension is a significant health care issue, estimated to affect 30-40% of adults in the developed world and increasing in prevalence in the developing countries. Despite the numerous single agent and combination therapies available, large swathes of patients ultimately prove unresponsive (refractory) to established therapies. Some of these patients are unable to adhere to a life-long course of drug therapy for a disease that is asymptomatic until its devastating conclusion. Others cases are refractory despite the best attempts of both patients and physicians. Both classes of patients are at high risk for end-organ damage leading to morbidity and mortality from their hypertension, and both would benefit from a procedure that 1) eliminates the need for lifelong pharmacotherapy, and 2) radically departs from pathways targeted by established anti-hypertensive therapy. This is especially true in populations for whom control of hypertension has clear and dramatic effects on survival. In dialysis-dependent patients, for example, control of hypertension reduces mortality risk by half.
The renal sympathetic nervous system, including both afferent and efferent fibers, runs adjacent to the renal artery. These fibers are critical for the initiation and maintenance of systemic hypertension. In both animal models and small clinical series, surgical methods of renal sympathetic removal of nerves (denervation), often via removal of the entire kidney (full nephrectomy), led to a dramatic lowering of blood pressure in patients who were otherwise refractory to all existing therapies. The risks in morbidity, mortality, and long term complications associated with a full nephrectomy, however, have prevented this therapy from wide adoption.